diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index ba4edde71a..0e64dc1dbb 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3200,7 +3200,7 @@ static struct config_int ConfigureNamesInt[] =
 			GUC_UNIT_BYTE
 		},
 		&pgstat_track_activity_query_size,
-		1024, 100, 102400,
+		1024, 100, 1048576,
 		NULL, NULL, NULL
 	},
 
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 46a06ffacd..55d3bfbfd0 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -569,7 +569,7 @@
 #track_counts = on
 #track_io_timing = off
 #track_functions = none			# none, pl, all
-#track_activity_query_size = 1024	# (change requires restart)
+#track_activity_query_size = 1024	# range 100B - 1MB (change requires restart)
 #stats_temp_directory = 'pg_stat_tmp'